利用者:Mats Halldin/Sandbox/25-Curves

Curves

Curves and Surfaces are objects just as meshes are objects except they are expressed in terms of mathematical functions, rather than as series of points.

Blender implements both Bézier curves and Non Uniform Rational B-Splines (NURBS) curves and surfaces. Both are defined in terms of a set of “control vertices” which define a “control polygon”, though each follow a different set of mathematical laws. The way the curve and the surface are interpolated might seem similar, at first glance, to Catmull-Clark subdivision surfaces. The curve is interpolated while the surface is attracted.

When compared to meshes, curves and surfaces have both advantages and disadvantages. Because curves are defined by less data, they produce nice results using less memory at modeling time, whereas the demands increase at rendering time.

Some modeling techniques, such as extruding a profile along a path, are only possible with curves. But the very fine control available on a per-vertex basis on a mesh, is not possible with curves.

There are times when curves and surfaces are more advantageous than meshes, and times when meshes are more useful. If you have read the pages on Basic Mesh Modeling and Advanced Mesh Modeling, and after you read this part, you will be able to choose whether to use meshes or curves.

Working with curves in Blender is fairly simple and surprisingly there are very few HotKeys when creating curves. It is what you do with those curves that really makes the difference. A curve by itself is just that, a curve. But a curve applied to another curve can create very complex objects.

Types

There are three types of curves:

Bézier

NURBS

Path

Common Properties

Shape

The shape...

2D/3D

Resolution

Preview/Render

Twisting

Tangent, Minimum, Z-Up...

Fill

Front/Back, Fill Deformed...

Textures

Use UV for Mapping, Auto Texture Space

Geometry

The geometry...

Modification

Bevel

Deform Objects

Taper, Bevel

Active Spline

In edit mode, ...

Cyclic

Resolution

Interpolation

Tilt/ Radius

Ease, BSpline, Cardinal, Linear

Path Animation

Described in DupliFrames...

See also

• Moving objects on a Path
• Methods of Deformation